Display device

ABSTRACT

A display device includes a display area that includes sub-pixels arranged in a matrix having rows and columns, pixels formed of the combination of two sub-pixels, from which light of different wavelength regions is emitted, image signal lines arranged by two columns, scanning signal lines arranged by one in each row, pixel transistors disposed in the respective sub-pixels in which one image signal line is connected to a source of each pixel transistor, and the one scanning signal line is connected to a gate of the pixel transistor, light emitting elements that each emit light on the basis of a potential of a drain of the pixel transistor, and a drive circuit that applies a conduction potential for rendering the pixel transistors conductive to two scanning signal lines corresponding to two adjacent rows at the same time.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese applicationJP2014-050809 filed on Mar. 13, 2014, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display device.

2. Description of the Related Art

In recent years, display devices using a self-luminous body such asorganic light emitting diodes (OLED: organic light emitting diode) havebeen put into practical use. As compared with a related art liquidcrystal display device, the display device including the organic EL(electroluminescent) display device using such an OLED employs theself-luminous body, and therefore not only is excellent in visibilityand response speed, but also does not require an auxiliary lightingdevice such as a backlight. Therefore, the display device using the OLEDcan be further thinned.

Japanese Patent No. 3438190 discloses a TFT display device that selectsadjacent scanning lines at the same time, and writes signals to bewritten to respective pixels with polarities opposite to each other.

Also, in the display device such as the organic EL display device, aswith the liquid crystal display device, high definition is desired, andlow power consumption is required. In a scanning line driving circuitfor driving the scanning lines of the organic EL display device, becausethe number of scanning lines increases more as the higher definitionprogresses, there is a need to increase a driving frequency, and powerconsumption increases. The increase in the power consumption is a factorfor preventing further higher definition.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above-mentionedcircumstances, and therefore an object of the present invention is toprovide a display device with reduced power consumption even when thehigher definition progresses.

According to the present invention, there is provided a display deviceincluding: a display area that includes a plurality of sub-pixelsarranged in a matrix having a plurality of rows and a plurality ofcolumns; pixels that are formed of the combination of at least two ofthe sub-pixels, from which light of different wavelength regions isemitted; image signal lines that are arranged by two in each of theplurality of columns; scanning signal lines that are arranged by one ineach of the plurality of rows; pixel transistors that are disposed inthe respective sub-pixels in which one of the two image signal lines isconnected to one of a source and a drain of each of the pixeltransistors, and the one scanning signal line is connected to a gate ofthe pixel transistor; light emitting elements that each emit light onthe basis of a potential of the other of the source and the drain of thepixel transistor; and a drive circuit that applies a conductionpotential for rendering the pixel transistors conductive to two of thescanning signal lines corresponding to two adjacent rows of theplurality of rows at the same time.

Also, in the display device according to the present invention, each ofthe pixels includes four of the sub-pixels that are substantiallyrectangular, and the four sub-pixels are arrayed in a matrix of two rowsand two columns so that two sides of each of the sub-pixels are adjacentto the two other sub-pixels.

Also, in the display device according to the present invention, thecombination of the two adjacent rows to which the conduction potentialis applied is different between a first timing at which the conductionpotential is applied, and a second timing at which the conductionpotential is applied subsequent to the first timing, and in this case,further, an image signal based on first data is supplied to the imagesignal lines at the first timing, and an image signal based on seconddata calculated according to the first data is supplied to the imagesignal lines at the second timing.

Also, the display device according to the present invention may furtherinclude drive transistors each having a gate connected to the other ofthe source and the drain of each of the pixel transistors, and a sourceand a drain one of which is connected to an anode of each of the lightemitting elements, and a metal layer formed of a planar electrode whichis connected to the other of the source and the drain of each of thedrive transistors, and overlaps with the display area in a plan view.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically illustrating an organic EL displaydevice according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view taken along a line II-II inFIG. 1;

FIG. 3 is a diagram illustrating an example of an organic EL displaydevice having no counter substrate;

FIG. 4 is a circuit diagram illustrating an example of a circuit in eachsub-pixel;

FIG. 5 is a diagram schematically illustrating a state of arrangement ofimage signal lines Pm and scanning signal lines Ln, which are input tothe circuit of each sub-pixel in a part of the display area;

FIG. 6 is a diagram illustrating a modification of the arrangement ofthe sub-pixels as with FIG. 5;

FIG. 7 is a diagram illustrating one case in which the arrangement ofthe sub-pixels in each pixel is different;

FIG. 8 is a diagram illustrating another case in which the arrangementof the sub-pixels in each pixel is different;

FIG. 9 is a cross-sectional view schematically illustrating eachsub-pixel; and

FIG. 10 is a plan view schematically illustrating arrangement of a firstelectrode and second electrodes.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the respective embodiments of the present invention will bedescribed with reference to the accompanying drawings. The disclosure ismerely exemplary, and appropriate changes that could be easily conceivedby those skilled in the art without departing from the spirit of thepresent invention are naturally included within the scope of the presentinvention. Also, in the drawings, for more clarification of theillustration, as compared with actual embodiments, widths, thicknesses,and shapes of respective parts may be schematically illustrated, but maybe merely exemplary, and do not limit the interpretation of the presentinvention. Also, in the present specification, and the respectivedrawings, the same elements as those described in the foregoing drawingsare denoted by identical symbols, and their detailed description will beappropriately omitted.

FIG. 1 schematically illustrates an organic EL display device 100 whichis a display device according to an embodiment of the present invention.As illustrated in FIG. 1, the organic EL display device 100 includes twosubstrates of a TFT (thin film transistor) substrate 120, and a countersubstrate 150, and a filler 191 (refer to FIG. 2) made of transparentresin is sealed between those substrates 120 and 150. A display area 205formed of pixels 210 arranged in a matrix is formed in the TFT substrate120 and the counter substrate 150 of the organic EL display device 100.In this example, it is assumed that each of the pixels 210 is formed ofplural sub-pixels 212 (to be described later), and in this embodiment,the sub-pixels 212 are arranged in x rows and y columns in the displayarea 205.

Also, the TFT substrate 120 is formed of a substrate made of aninsulating material of transparent glass or resin, and a drive IC(integrated circuit) 182 is mounted on the TFT substrate 120. The driveIC 182 is a drive circuit that applies a potential for conductingbetween a source and a drain of a pixel transistor 220 (to be describedlater) arranged in each of the sub-pixels 212 to a scanning signal lineLn (n is a natural number of y or lower) connected to a gate of thepixel transistor 220, and also applies a voltage corresponding to agradation value of each sub-pixel 212 to an image signal line Pm (m is anatural number of x or lower). The TFT substrate 120 is fitted with anFPC (flexible printed circuits) 181 for receiving an image signal froman external. Also, this embodiment employs a top emission organic ELdisplay device in which light is emitted toward a side on which a lightemitting layer of the TFT substrate 120 is formed as indicated by anarrow in FIG. 1, but may employ a bottom emission organic EL displaydevice.

FIG. 2 is a schematic cross-sectional view taken along a line II-II inFIG. 1. As illustrated in the cross-sectional view, a TFT circuit layer160 in which a TFT circuit is formed, plural organic EL elements 130that are plural light emitting elements formed on the TFT circuit layer160, and a sealing film 125 that blocks moisture over the organic ELelement 130 are formed on the TFT substrate 120. The same number oforganic EL elements 130 as the number of sub-pixels 212 included in eachof the pixels 210 is formed. However, for clarity in illustration ofFIG. 2, the organic EL elements 130 are simplified. Also, color filtersthat transmit light of the respective different wavelength regions of,for example, three or four colors, and a black matrix that is a lightshielding film that blocks light emitted from boundaries of therespective sub-pixels 212 are formed on the counter substrate 150. Thefiller 191 between the TFT substrate 120 and the counter substrate 150is sealed with a sealant 192.

This embodiment employs a configuration having the counter substrate 150as illustrated in FIG. 2, but can employ a configuration having nocounter substrate 150 as illustrated in FIG. 3. Also, as illustrated inFIG. 3, the drive IC 182 may be arranged on the FPC 181. In particular,when the TFT substrate 120 is made of a flexible resin material, the TFTsubstrate 120 may be configured integrally with the FPC 181. Also, inthis embodiment, the organic EL elements 130 emit white light, and thecolor filters are used to transmit the light of the wavelength regionsof three or four colors. Alternatively, the organic EL elements 130 maybe configured to emit the light of the respective different wavelengthregions of, for example, three or four colors.

FIG. 4 is a circuit diagram illustrating an example of a circuit in eachof the sub-pixels 212. The operation of the circuit for light emissionwill be described with reference to FIG. 4. An image signalcorresponding to a gradation value of each of the sub-pixels 212 issupplied to the image signal line Pm, and the pixel transistor 220 isrendered conductive on the basis of the signal of the scanning signalline Ln, to thereby store a voltage based on the gradation value in atleast one of capacitors 241 and 242. A drive transistor 230 allows acurrent based on a potential stored in at least one of the capacitors241 and 242 to flow into the organic EL element 130 to emit light. Acathode side of the organic EL element 130 is connected to a lowreference potential VSS, and a source side (a side opposite to theorganic EL element 130 side) of the drive transistor 230 is connected toa high reference potential line held to a high reference potential VDD.In this example, it is assumed that a circuit surrounded by a dashedline except for the scanning signal line Ln and the image signal line Pmfor the purpose of later description is a pixel circuit 215.

Both of the respective capacitors 241 and 242 maybe formed, or any onecapacitor may be formed. In this circuit diagram, a p-type semiconductoris used, but an n-type semiconductor may be used. Also, the circuit inFIG. 6 is a simple circuit for describing the control of the lightemission, and has two transistors. Alternatively, the circuit may beconfigured to have three or more transistors, or may include anothercontrol line or capacitor. The configuration of the circuit can bearbitrarily determined.

FIG. 5 is a diagram schematically illustrating a state of arrangement ofthe image signal lines Pm and the scanning signal lines Ln, which areinput to the circuit of each of the sub-pixels 212 in a part of thedisplay area 205. In FIG. 5, each of the pixels 210 is formed of foursubstantially rectangular sub-pixels 212 that emit the light of thewavelength regions corresponding to four kinds of colors of R (red), G(green), B (blue), and W (white). The four sub-pixels 212 are aligned ina matrix of two rows and two columns so as to come in contact with twosides of two other sub-pixels 212 in the same pixel 210. Therefore, eachof the pixels 210 is configured by the sub-pixels 212 located in twoadjacent rows.

One scanning signal line Ln is arranged for the row of each sub-pixel,and two image signal lines Pma and Pmb are arranged for the column ofeach sub-pixel 212. For example, image signal lines P1 a and P1 b arearranged in a first column of the sub-pixels 212. Also, the circuits ofthe sub-pixels 212 in odd rows, that is, the sub-pixels 212 connected tothe scanning signal lines L1, L3 . . . are connected to the image signallines Pmb (for example, P1 b, P2 b, . . . ) of the two image signallines Pma and Pmb, and the circuits of sub-pixels 212 in even rows, thatis, the sub-pixels 212 connected to the scanning signal lines L2, L4, .. . are connected to the image signal lines Pma (for example, P1 a, P1b, . . . ).

Also, because the drive IC 182 which is the drive circuit can applypotentials different from each other to the image signal lines Pma andPmb, the drive IC 182 can apply a conduction potential for conductingthe transistor of each pixel circuit 215 to one of the scanning signallines Ln in the odd rows, and one of the scanning signal lines Ln in theeven rows at the same time, and can apply the different potentialscorresponding to the gradation values of the respective sub-pixels 212to the pixel circuit 215.

For example, when the drive IC 182 performs scanning so as to apply theconduction potential to the two scanning signal lines L1 and L2 in twoadjacent rows at the same time, and apply the conduction potential tothe scanning signal lines L3 and L4 in a next timing (timing ofhorizontal synchronization), the drive IC 182 can apply thecorresponding gradation voltages to the respective sub-pixels 212through the image signal lines Pma and Pmb, and can halve a frequency(horizontal synchronous frequency) for applying the conduction potentialas compared with a case in which the scanning signal lines Ln arescanned one by one. For example, the above operation is conducted by thedrive circuit of the scanning signal lines arranged within the drive IC182 with the results that the power consumption of the drive circuitthat scans the scanning signal lines can be suppressed, and the powerconsumption of the overall organic EL display device 100 can be reduced.Also, a scale of the drive circuit can be reduced, and a frame area canbe reduced. On the other hand, even if the higher definition progresses,an increase in the frequency for scanning the scanning signal lines Lnassociated with the higher definition can be suppressed, as a result ofwhich an increase in the power consumption can be suppressed.

Also, another way to scan the scanning signal line in the arrangement ofthe image signal lines Pm and the scanning signal lines Ln in FIG. 5will be described. When a period of the vertical synchronization iscalled “frame”, in odd frames scanning is performed for each two rows,and scanning for applying the conduction potential to every two rows isperformed in odd frames so that the conduction potential is firstapplied to the scanning signal lines L1 and L2 (A in FIG. 5) at the sametime, and the conduction potential is then applied to the scanningsignal lines L3 and L4 at the same time. That is, among the adjacentscanning signal lines, the scanning is performed for applying theconduction potential to the odd-numbered scanning signal line Ln, andthe even-numbered scanning signal line Ln larger than the odd-numberedscanning signal line Ln by 1 at the same time. On the other hand, ineven frames, scanning is performed so that after the conductionpotential has been first applied to only the scanning signal line L1,the conduction potential is applied to the scanning signal lines L2 andL3 (B in FIG. 5), and the conduction potential is then applied to thescanning signal lines L4 and L5. That is, the scanning is performed forapplying the conduction potential to the even-numbered scanning signalline Ln, and the odd-numbered scanning signal line Ln larger than theeven-numbered scanning signal line Ln by 1, of the adjacent scanningsignal lines Ln except for the first scanning signal line L1 (and a lastscanning signal line Ly) at the same time.

That is, scanning can be performed so that the combination of the twoadjacent scanning signal lines Ln (or the rows of the sub-pixels 212) towhich the conduction potential is applied at the same time is differentbetween a first timing that is timing of the odd frame when theconduction potential is applied to a certain scanning signal line Ln,and a second timing that is timing of the even frame which is a nexttiming when the conduction potential is applied to that scanning signalline. The combination of the scanning signal lines Ln and Ln+1 to whichthe conduction potential is applied at the same time is thus changedwith the results that the occurrence of flicker of a display image orthe like can be suppressed, and the display quality can be enhanced.

Further, the above scanning is performed, and for example, in theabove-mentioned even frame, a complementary image formed by second datacalculated on the basis of first data of images displayed in odd framesbefore and after the even frame can be displayed. In this case, thesecond data of the complementary image can be calculated in the drive IC182, or an information processing unit for processing information forinputting information to the drive IC 182. The second data of thecomplementary image in the pixels to which the conduction potential isapplied at the same time in the even frame may be calculated on thebasis of the data of the pixels around the previous frame, calculated onthe basis of the data around the subsequent image, or calculated withthe use of both of those data. In calculation of the complementaryimage, for example, a statistical process such as averaging can besimply used. Alternatively, so-called various super-resolutionprocessing techniques that enable higher image quality to be expectedcan be also applied. In this way, particularly, the display of a movingpicture and the like can be smoothed with the use of the complementaryimage. In this case, the odd-numbered frames are driven at a normaldriving frequency to thereby display the complementary image that isdifferent in the combination of the scanning signal lines Ln and Ln+1 inthe even-numbered frames. As a result, the image finer and smoother thanan actual resolution can be displayed. Also, even when the image higherin vertical resolution is originally entered, the high definition imagecan be easily displayed by the display device with a limited number ofscanning lines.

The vertical scanning direction has been described above, but the sameconcept can be applied to the horizontal scanning to display the imagewith higher resolution. That is, in a first frame, one pixel isconfigured by data for four sub-pixels of RGBW in the combination of P1a and P1 b with P2 a and P2 b for L1 and L2, but in a second frame, datafor one pixel is configured by four sub-pixels of RGBW with the use ofthe combination of P2 a and P2 b with P3 a and P3 b.

As described above, since, for example, an ultra-high definition imagethat exceeds the number of pixels of the display can be easily displayedwith the use of a combination technique for each of horizontal andvertical frames. Therefore, the display device can operate with thepower consumption lower than that of the display device having theoriginal number of pixels. This concept can be applied to all of thedisplay devices including a liquid crystal display device without beinglimited to the organic EL element.

FIG. 6 is a diagram illustrating a modification of the arrangement ofthe sub-pixels 212 as with FIG. 5. FIG. 6 is different from FIG. 5described above in that the image signal lines Pma and Pmb are arrangedto sandwich the pixel circuit 215 therebetween. With this arrangement,because lines that extend from the respective pixel circuits 215 to theimage signal lines Pma can be wired without crossing the image signallines Pmb, an area for wiring can be reduced, and a capacity and anopening can be increased. Also, because a complex wiring is reduced, amanufacturing process is simplified, and the yield can be improved.

FIG. 7 is a diagram illustrating one case in which the arrangement ofthe sub-pixels 212 in each of the pixels 210 is different. In FIG. 7,each of the pixels 210 includes the substantially rectangular sub-pixels212 that emit the light of the wavelength regions corresponding to threekinds of colors of R(red), G(green), and B(blue), and the sub-pixels 212of a so-called stripe arrangement in which the sub-pixels 212 of thesame color are aligned in the row (vertical) direction are configured.Also, pixels in a row A and pixels in a row B form a substantial square260. In the case of this pixel arrangement, each of the pixels 210 isnot configured to cross two rows of the sub-pixels 212, but each of thepixels 210 is configured to fall within one row. Even in thisconfiguration, as with FIG. 5, the conduction potential is applied tothe scanning signal lines Ln and Ln+1 at the same time, thereby beingcapable of obtaining the same effects. Also, as described above, thedrive circuit performs the operation of changing the combination of thescanning signal lines Ln and Ln+1 to which the conduction potential isapplied at the same time, thereby being capable of suppressing theoccurrence of the flicker of the display image and the like, andenhancing the display quality. Also, the drive circuit performs theoperation using the complementary image, thereby being capable ofparticularly smoothing the display of a moving image or the like, andfurther capable of obtaining the image display finer and smoother thanthe actual resolution.

In this example, three kinds of pixels of RGB are arranged in ahorizontal direction, and the same color is arranged in a verticaldirection. However, one pixel is configured by RGB of Ln and RGB ofLn+1, thereby being capable of performing driving for changing thecombination of the odd-numbered frame with the even-numbered frame. Inaddition, the operation of changing the combination of RGB in thehorizontal direction to RGB, GBR, and BRG in the stated order iscombined, thereby being capable of displaying the image with higherdefinition.

FIG. 8 is a diagram illustrating another case in which the arrangementof the sub-pixels 212 in each pixel 210 is different. In FIG. 8, as withFIG. 7, each of the pixels 210 includes the substantially rectangularsub-pixels 212 that emit the light of the wavelength regionscorresponding to three kinds of colors of R(red), G(green), and B(blue).However, FIG. 8 is different from FIG. 7 in that each of the pixels 210includes two sub-pixels 212 of G, and one pixel 210 is configured byfour sub-pixels in total. Also, any one of RG and BG is repetitivelyaligned in a longitudinal direction. Even in this pixel configuration,the same operation as that in the case of the configuration of thesub-pixels 212 in FIG. 7 can be performed, and the same effects can beobtained.

FIG. 9 is a cross-sectional view schematically illustrating each of thesub-pixels 212. In FIG. 9, the illustration of the filler 191 and thecounter substrate 150 is omitted, and only the TFT substrate 120, theTFT circuit layer 160, the organic EL elements 130, and the sealing film125 are illustrated. As illustrated in FIG. 9, the TFT circuit layer 160includes the pixel transistor 220 and the drive transistor 230. Also,the TFT circuit layer 160 includes a first electrode 171 that isarranged between the TFT substrate 120, and the pixel transistor 220 aswell as the drive transistor 230, overlaps with at least the pluralsub-pixels 212 in a plan view, for example, overlaps with the overalldisplay area 205. Also, a second electrode 172 made of a conductivematerial which forms a capacitor in cooperation with the first electrode171 is arranged on a side of the first electrode 171 opposite to the TFTsubstrate 120 side, in this example, between the first electrode 171,and the pixel transistor 220 as well as the drive transistor 230,through insulating films 163 and 165.

In this example, the first electrode 171 is made of metal containing atleast one of Mo (molybdenum) and W (tungsten), and can function as asolid electrode that covers the display area 205. With the use ofrefractory metal containing Mo or W, even if a heat treatment isperformed during manufacture, there is no transformation caused bymelting or the like, and the quality can be kept. In particular, it iseffective that a semiconductor layer 224 or 234 is made of semiconductorsuch as polysilicon. The second electrode 172 can be made of refractorymetal containing at least one of Mo and W, and the same effects can beobtained in this case. Also, with the use of a material having a highdielectric constant such as SiN for the insulating film 163, an electriccapacitance formed by the first electrode 171 and the second electrode172 can be more increased. In this example, each of the secondelectrodes 172 is formed for one sub-pixel 212, independently, and isconnected to a circuit within the sub-pixel 212. In addition, a basefilm 161 made of an insulating material such as SiNx is formed.

The drive transistor 230 includes a gate 231, a source 232, and a drain233, and the semiconductor layer 234 is arranged between the source 232and the drain 233. Also, the pixel transistor 220 includes a gate 221, asource 223, and a drain 222, and the semiconductor layer 224 is arrangedbetween the source 223 and the drain 222. The drain 222 of the pixeltransistor 220 is connected to the gate of the drive transistor 230. Aninsulating film 166 made of an insulating material such as SiNx isformed between the semiconductor layers 224, 234, and the gates 221,231, and an insulating film 167 made of an insulating material such asSiNx is formed on the gates 221 and 231. A planarizing film 168 made ofan organic insulating material is formed on the pixel transistor 220 andthe drive transistor 230.

Also, each of the organic EL elements 130 includes an anode electrode131 connected to the drain 233 of the drive transistor 230 through acontact hole pierced in the planarizing film 168, a pixel separationfilm 135 made of an organic insulating material which covers an end ofthe anode electrode 131, and insulates the anode electrode 131 fromanother anode electrode 131 of the adjacent sub-pixel 212, an organiclayer 132 that includes a light emitting layer formed to come in contactwith the anode electrode 131 of each of the sub-pixels 212, and coverthe display area 205, and a cathode electrode 133 that is a transparentconductive film made of complex oxide of indium and tin, or a complexoxide of indium and zinc. In this example, an area in which the anodeelectrode 131 comes in contact with the organic layer 132 functions as alight emitting area LE that emits light.

In the configuration described above, the first electrode 171 isconnected to the source of the drive transistor 230, and also connectedto the high reference potential VDD in plural locations outside of thedisplay area 205 to hold a voltage of the high reference potential VDD.Also, the second electrode 172 is connected to the gate 231 (that is,the drain 222 of the pixel transistor 220) of the drive transistor 230.With the above configuration, the first electrode 171 and the secondelectrode 172 form the capacitor 241 in the circuit diagram of FIG. 6.Therefore, because the large capacitor 241 can be formed by the firstelectrode 171 and the second electrode 172, a current to be supplied tothe organic EL elements 130 can be stabilized. Also, because the firstelectrode 171 and the second electrode 172 are formed on the TFTsubstrate 120 side of the drive transistor 230 and the pixel transistor220, the capacitor can be formed without affecting the circuitconfiguration. Also, because the first electrode 171 is formed to beconnected to the high reference potential VDD, and overlap with thedisplay area 205, the first electrode 171 can provide the high referencepotential VDD of a more uniform potential in the display area 205.Further, because the first electrode 171 does not require an additionalline for supplying the high reference potential VDD in the circuitwithin each of the sub-pixels 212, the drive transistor 230 or the pixeltransistor 220 can be formed with a larger size. That is, as indicatedby the image signal lines Pma and Pmb in FIG. 5, even when two of theimage signal lines Pm are arranged in each row of the sub-pixels 212,there is no need to provide an additional line for supplying the highreference potential VDD, and an area and an opening area used for thecircuit can be widely kept. Also, with the configuration in which thefirst electrode 171 is connected to the plural locations outside of thedisplay area 205, a further stable potential can be supplied. Also,because the first electrode 171 is formed to overlap with the displayarea 205, a heat generated in the organic EL elements 130 can beradiated with high efficiency, and electromagnetic noise generated inthe circuit can be also blocked.

In the above-mentioned embodiments, the first electrode 171 is connectedto the source of the drive transistor 230, and the second electrode 172is connected to the gate 231 of the drive transistor 230. Alternatively,in the display area 205, the first electrode 171 is connected to the lowreference potential VSS connected with the cathode side of the organicEL elements 130, and the second electrode 172 is connected to the drain233 of the drive transistor 230, thereby being capable of forming acapacitor 243.

FIG. 10 is a plan view schematically illustrating arrangement of thefirst electrode 171 and the second electrodes 172. As indicated in FIG.10, the second electrodes 172 overlap with the first electrode 171 thatextensively overlaps with the overall display area 205, and are arrangedfor each of the sub-pixels 212, independently. Also, the first electrode171 is provided with slits 178 which are holes in plural locations.Because the first electrode 171 forms the capacitors in cooperation withthe second electrodes 172, the slits 178 are provided in areas that donot overlap with the second electrodes 172. Also, outside of the displayarea 205, the first electrode 171 is electrically connected to pluralterminals 185, and held to the high reference potential VDD.

The slits 178 can reduce a stress generated within the first electrode171, and also can efficiently radiate heat. In FIG. 10, the slits 178are shaped into holes, but the slits 178 may extend from one end to theother end so as to cut off the first electrode 171. In this case, thefirst electrode 171 is formed to overlap with at least a part of thedrive transistor 230 and a part of the pixel transistor 220 in a planview, and the first electrode 171 is connected to a fixed potential suchas the high reference potential VDD.

While there have been described what are at present considered to becertain embodiments of the invention, it will be understood that variousmodifications maybe made thereto, and it is intended that the appendedclaims cover all such modifications as fall within the true spirit andscope of the invention.

What is claimed is:
 1. A display device, comprising: a display area thatincludes a plurality of sub-pixels arranged in a matrix having aplurality of rows and a plurality of columns; pixels that are formed ofthe combination of at least two of the sub-pixels, from which light ofdifferent wavelength regions is emitted; image signal lines that arearranged by two in each of the plurality of columns; scanning signallines that are arranged by one in each of the plurality of rows; pixeltransistors that are disposed in the respective sub-pixels in which oneof the two image signal lines is connected to one of a source and adrain of each of the pixel transistors, and the one scanning signal lineis connected to a gate of the pixel transistor; light emitting elementsthat each emit light on the basis of a potential of the other of thesource and the drain of the pixel transistor; and a drive circuit thatapplies a conduction potential for rendering the pixel transistorsconductive to two of the scanning signal lines corresponding to twoadjacent rows of the plurality of rows at the same time.
 2. The displaydevice according to claim 1, wherein each of the pixels includes thesub-pixels in two rows of the plurality of rows of the sub-pixels. 3.The display device according to claim 2, wherein each of the pixelsincludes four of the sub-pixels that are substantially rectangular, andthe four sub-pixels are arrayed in a matrix of two rows and two columnsso that two sides of each of the sub-pixels are adjacent to the twoother sub-pixels.
 4. The display device according to claim 1, whereinthe combination of the two adjacent rows to which the conductionpotential is applied is different between a first timing at which theconduction potential is applied, and a second timing at which theconduction potential is applied subsequent to the first timing.
 5. Thedisplay device according to claim 4, wherein an image signal based onfirst data is supplied to the image signal lines at the first timing,and an image signal based on second data calculated according to thefirst data is supplied to the image signal lines at the second timing.6. The display device according to claim 1, further comprising: drivetransistors each having a gate connected to the other of the source andthe drain of each of the pixel transistors, and a source and a drain oneof which is connected to an anode of each of the light emittingelements; and a metal layer formed of a planar electrode which isconnected to the other of the source and the drain of each of the drivetransistors, and overlaps with the display area in a plan view.